Unit cell of display panel including integrated tft photodetector

Abstract

A unit pixel arranged along with a display pixel in each pixel of a display panel is provided. The unit pixel may include a thin-film transistor (TFT) photodetector including an active layer formed of amorphous silicon or polycrystalline silicon on an amorphous transparent substrate, and at least one transistor electrically coupled to the TFT photodetector and configured to generate a voltage output from photocurrent generated from the active layer.

What is claimed is: 
     
         1 . A unit pixel of a display panel having image sensing function, the unit pixel comprising:
 a light emitting area;   a thin-film transistor (TFT) photodetector including an active layer formed of amorphous silicon or polycrystalline silicon on an amorphous transparent substrate; and   at least one transistor electrically coupled to the TFT photodetector and configured to generate a voltage output from photocurrent generated from the active layer,   wherein the active layer includes a wavelength extension layer, which is formed by a plurality of localized energy levels in the active layer.   
     
     
         2 . The unit pixel of  claim 1 , wherein the light emitting area is formed near to the TFT photodetector on the same layer. 
     
     
         3 . The unit pixel of  claim 2 , further comprising a driving switch,
 wherein the driving switch controls driving of the light emitting area or controls the TFT photodetector.   
     
     
         4 . The unit pixel of  claim 1 , wherein the at least one transistor converts the photocurrent into the voltage output based on parasitic capacitance between the at least one transistor, caused by the photocurrent generated from the active layer. 
     
     
         5 . The unit pixel of  claim 4 , wherein the at least one transistor includes a select transistor, and
 wherein when the select transistor is turned on, the parasitic capacitance is generated.   
     
     
         6 . The unit pixel of  claim 1 , wherein the at least one transistor converts photocurrent into the voltage output, the photocurrent being generated by directly charging a capacitor coupled to a transistor corresponding to a source follower with the photocurrent generated from the active layer. 
     
     
         7 . The unit pixel of  claim 5 , wherein the at least one transistor includes a select transistor, and
 wherein when the select transistor is turned on, a capacitor of an IVC circuit is charged, among capacitors coupled to the transistor corresponding to the source follower, and the charged photocurrent is converted into a voltage which is an output of the IVC circuit.   
     
     
         8 . The unit pixel of  claim 1 , wherein a pixel structure is determined based on a thickness of the active layer. 
     
     
         9 . The unit pixel of  claim 8 , further comprising a transistor coupled to the active layer and configured to control residual charges in a neutral area, when the thickness of the active layer is equal to or larger than a reference value. 
     
     
         10 . The unit pixel of  claim 1 , wherein the TFT photodetector uses light generated from the display panel as a light source for a sensor.